I remember one time at work, during my break, I caught my co-worker taking pictures of me from the other table. I have no idea how long she was doing this or how many pictures she took. I initially seen her holding her phone when I first sat down, not really paying it any attention. About half hour later, being bored to death my eyes began to wander, eventually stumbling upon my co-worker aiming her phone at me with a blinking green light. That green light is purposely exposed to the person facing the phone, alerting them that the camera is active. I confronted her, and she thought it was funny blah blah etc Making the click sound mandatory is great protection to everyones privacy.